Triangle T(n,k) of arctangent numbers: expansion of arctan(x)^n/n!.

Terms

a(0) =1a(1) =0a(2) =1a(3) =-2a(4) =0a(5) =1a(6) =0a(7) =-8a(8) =0a(9) =1a(10) =24a(11) =0a(12) =-20a(13) =0a(14) =1a(15) =0a(16) =184a(17) =0a(18) =-40a(19) =0a(20) =1a(21) =-720a(22) =0a(23) =784a(24) =0a(25) =-70a(26) =0a(27) =1a(28) =0a(29) =-8448